Allergic contact dermatitis is a form of contact dermatitis. It appears in the form of a rash and is the manifestation of an allergic response caused by contact with certain chemicals.
Irritants and allergens can cause allergic contact dermatitis. Although some people may have been exposed to substances for years without any symptoms, the allergic reaction may develop at any time and can do so with immediate effect. Common causes of allergic contact dermatitis include acids, alkalis, acetone, soaps, detergents, metals (such as nickel often found in jewelry), rubber, latex, cosmetics, antiperspirant deodorants, plants (such as poison ivy) and medications.
The symptoms vary from person to person. Irritant and allergic contact dermatitis usually occurs on areas of the body that have been directly exposed to the substance, but it may also spread to other areas. Possible symptoms include itching, redness, swelling, blisters, the seepage of fluid, or dry and scaly skin. Rubbing or scratching the affected area may cause infection and worsen the symptoms.
The doctor will conduct history-taking for possible chemicals, a physical examination and, in some cases, may refer the patient to a dermatologist for further investigation.
Treatment focuses on relieving the symptoms through various means of skin care, including:
- Wash the area with water and a mild soap. Dry the area. Avoid squeezing or opening any blisters because this may cause infection. Cover blisters with a clean dressing.
- Use medications
- Corticosteroid cream or ointment
- In severe cases, oral prednisolone and antihistamines may be required for relieve.
The above treatments are aimed at relieving the symptoms. However, for effective treatment, it is important to identify the cause of the rashes and any other symptoms, and then take steps to avoid coming into contact with it. In some cases, the doctor may recommend a patch test. Small amounts of potential allergens are applied to adhesive patches, which are then placed on the skin. The patches remain on the skin for 2-3 days. After this period, the doctor checks the skin reaction under each of the patches to identify any redness and swelling which would then be indicative of the allergens to be avoided.